MALVERN, Pa. and SAN DIEGO—PhaseBio Pharmaceuticals, Inc. has signed an agreement with Viamet Pharmaceuticals Holdings, LLC and its wholly-owned subsidiary, Selenity Pharmaceuticals (Bermuda) Ltd., to acquire all of the assets and intellectual property rights related to certain novel aldosterone synthase inhibitors. The agreement includes Viamet’s lead development compound, formerly known as SE-6440 or VT-6440.

PhaseBio has designated the lead development compound as PB6440. The company plans to develop the compound for treatment-resistant hypertension. PB6440 is a highly selective aldosterone synthase inhibitor that modulates the renin-angiotensin-aldosterone system, which plays a critical role in regulation of systemic blood pressure.

The terms of the agreement include an upfront payment by PhaseBio; development, approval and net sales milestones; and tiered royalties on global net sales. PhaseBio will be responsible for all development, manufacturing and commercialization of PB6440.

“Hypertension is one of the key risk factors for cardiovascular disease and has been linked to significant morbidity and mortality,” said Jonathan Mow, chief executive officer of PhaseBio. “Despite a broad array of therapeutic options available to manage blood pressure, a significant proportion of hypertensive patients are still not achieving the increasingly stringent blood-pressure goals set by the American College of Cardiology and the American Heart Association. PB6440 represents an exciting, new potential treatment option for patients with treatment-resistant hypertension, and we believe it is an excellent strategic fit with PhaseBio’s pipeline of novel therapies for specialty cardiovascular diseases with high unmet need.”

In preclinical studies, PB6440 was observed to be a highly potent and selective inhibitor of aldosterone synthase (CYP11B2) versus the closely-related steroid 11β-hydroxylase enzyme (CYP11B1). PB6440 demonstrated dose-dependent aldosterone reduction without a significant increase in 11-deoxycorticosterone or deoxycortisol in both rodent and primate models. The oral bioavailability and pharmacokinetic profiles appear suitable for once-daily dosing in humans. To date, no evidence of toxicity has been observed in either in vitro toxicity studies or in animal models, including primates.

“Over the past decade, the dramatic decline in research and development focused on novel treatment options for hypertension, coupled with an alarming increase in global obesity rates, has led to a very high unmet need for novel approaches to blood pressure management. Recent draft guidance from the U.S. Food and Drug Administration highlights this unmet need and describes a streamlined regulatory path for novel drugs to treat resistant hypertension without the need for large outcomes studies,” noted John Lee, M.D., Ph.D., chief medical officer of PhaseBio. “Based on data seen to date, we believe targeting elevated aldosterone levels in patients with hypertension who are not adequately controlled on a background of multiple antihypertensive drugs represents a promising new approach. We are excited to have the opportunity to advance PB6440 as part of our growing portfolio of novel cardiovascular therapies.”

PhaseBio is planning to initiate clinical development of PB6440 pending the completion of nonclinical Investigational New Drug Application (IND)-enabling studies, which are planned for 2020. The company hopes to complete an IND filing and a first-in-human study in early 2021.